#include <stdio.h>

int climb(int n);
int main()
{
	int n;
	scanf("%d",&n);
	printf("%d\n",climb(n));
	return 0;
}


int climb(int n)
{
	int count=0;
	if(n>=0&&n<=20)
		for(int tj3=n/3;tj3>0;tj3--)
			for(int tj2=n/2;tj2>0;tj2--)
				for(int tj1=n;tj1>0;tj1--)
					if(3*tj3+2*tj2+tj1==n)
						count++;
	return count;
}
